From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9719AC04AA7 for ; Mon, 13 May 2019 15:22:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 691E22084A for ; Mon, 13 May 2019 15:22:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557760938; bh=9+UsjQpwyDy1tj3CGP56pEdTyFHY73ZlBK305NAVzoA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=mRk3dT4u6alze1E4dEF5k+0UM+aoBOW/+VpvK6+4OTx2FiOPDGd3FXRzmZFysDjj+ Ee4fSqMDV8ke8JBAVgCrbtLMV3se61ke2NQSt7ipZywM2tKsTSmG3BTmY0q2vY+H/s VAVtJBkbA0ZT1paN+w2ftAMelGCCsomORtlcQcX4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729349AbfEMPWR (ORCPT ); Mon, 13 May 2019 11:22:17 -0400 Received: from mga04.intel.com ([192.55.52.120]:7085 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727458AbfEMPWQ (ORCPT ); Mon, 13 May 2019 11:22:16 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 May 2019 08:22:14 -0700 X-ExtLoop1: 1 Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by orsmga002.jf.intel.com with ESMTP; 13 May 2019 08:22:13 -0700 Date: Mon, 13 May 2019 09:16:52 -0600 From: Keith Busch To: Christoph Hellwig Cc: Mario.Limonciello@dell.com, keith.busch@intel.com, sagi@grimberg.me, linux-nvme@lists.infradead.org, rafael@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, kai.heng.feng@canonical.com Subject: Re: [PATCH] nvme/pci: Use host managed power state for suspend Message-ID: <20190513151652.GB15437@localhost.localdomain> References: <20190510212937.11661-1-keith.busch@intel.com> <0080aaff18e5445dabca509d4113eca8@AUSX13MPC105.AMER.DELL.COM> <955722d8fc16425dbba0698c4806f8fd@AUSX13MPC105.AMER.DELL.COM> <20190513143754.GE15318@localhost.localdomain> <7ab8274ef1ce46fcae54a50abc76ae4a@AUSX13MPC105.AMER.DELL.COM> <20190513145708.GA25897@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190513145708.GA25897@lst.de> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 13, 2019 at 04:57:08PM +0200, Christoph Hellwig wrote: > On Mon, May 13, 2019 at 02:54:49PM +0000, Mario.Limonciello@dell.com wrote: > > And NVME spec made it sound to me that while in a low power state it shouldn't > > be available if the memory isn't available. > > > > NVME spec in 8.9: > > > > "Host software should request that the controller release the > > assigned ranges prior to a shutdown event, a Runtime D3 event, or any other event > > that requires host software to reclaim the assigned ranges." > > The last part of the quoted text is the key - if the assigned range > is reclaimed, that is the memory is going to be used for something else, > we need to release the ranges. But we do not release the ranges, > as we want to keep the memory in use so that we can quickly use it > again. Yes, this. As far as I know, the host memory range is still accessible in the idle suspend state. If there are states in which host memory is not accessible, a reference explaining the requirement will be most helpful.